The Living World: Ecosystems and Biodiversity Flashcards
a system of interconnected elements: a community of living organisms and its environment
ecosystem
living components of an ecosystem
biotic
nonliving components in an ecosystem
abiotic
the change in a population’s genetic composition over time
evolution
made to model evolution; can encompass many types of species, or can be very specific
phylogenetic tree
the formation of new and distinct species in the course of evolution
speciation
a group of organisms that are capable of breeding with one another—and incapable of breeding with other species
species
individual organisms that are better adapted for their environment will live and reproduce
evolutionary fitness
a habitat selects certain organisms to live and reproduce and others to die; beneficial characteristics are inherited and unfavorable characteristics become less common
natural selection
any cause that reduces reproductive success (fitness) in a portion of the population
selective pressure
the stock of different genes in an interbreeding population
gene pool
the accumulation of changes in the frequency of alleles (versions of a gene) over time due to sampling errors—changes that occur as a result of random chance
genetic drift
small-scale changes over a relatively short period of time in a population
microevolution
large-scale patterns of evolution within biological organisms over a long period of time
macroevolution
a species cannot adapt quickly enough to environmental change and all members of the species die
extinction
true extinction of a species
biological extinction
so few individuals of a species that the species can no longer perform its ecological function
ecological extinction
few individuals exist but the effort needed to locate and harvest them is not worth the expense
commercial/economic extinction
a group of organisms of the same species
population
populations of different species occupy the same geographic area
community
the total sum of a species’ use of the biotic and abiotic resources in its environment
niche
the area of environment where an organism or ecological community normally lives or occurs
habitat
has a narrow niche and can only live in a certain habitat
specialist
has a broad niche, is highly adaptable, and can live in varied habitats
generalist
two individuals—of the same species or of different species—are competing for resources in the environment
competition
two individuals competing are from the same species
intraspecific competition
two individuals competing are different species
interspecific competition
when two different species in a region compete and the better adapted species wins
competitive exclusion
no two species can occupy the same niche at the same time and that the species that is less fit to live in the environment will relocate, die out, or occupy a smaller niche
Gause’s principle
a species occupies a smaller niche than it would in the absence of competition
realized niche
the niche species would have if there was no competition
fundamental niche
different species use slightly different parts of the habitat, but rely on the same resource
resource partitioning
one species feeds on another, and it drives changes in population size
predation
species that feeds on other organisms
predator
gets eaten
prey
close, prolonged associations between two or more different organisms of different t species that may, but do no necessarily, benefit each member
symbiotic relationships
both species benefit
mutualism
one organism benefits while the other is neither helped nor hurt
commensalism
one species is harmed and the other benefits
parasitism
ecosystems that are based on land
biomes
ecosystems that are based in water
aquatic life zones
transitional area where two ecosystems meet
ecotones
smaller regions within ecosystems that share similar physical features
ecozones/ecoregions
hardwood trees, 75-250 cm rainfall, rich soil with high organic content (NA, E, AUS, and E ASIA)
deciduous forest
tall trees with few lower limbs, vines, epiphytes, plants adapted to low light intensity, 200-400 cm rainfall, poor quality soil (SA, W AFR, and SE ASIA)
tropical rainforest
sod-forming grasses, 10-60 cm rainfall, rich soil (NA plains, prairie, and savanna, RUS steppes, SA velds, ARG pampas)
grasslands
coniferous trees, 20-60 cm rainfall, soil is acidic due to vegetation (N NA, N EARASIA)
coniferous forest/taiga
herbaceous plants, less than 25 cm rainfall, soil is permafrost (northern latitudes of NA, EUR, RUS)
tundra
small trees with large, hard evergreen leaves, spiny shrubs, 50-75 cm rainfall, soil is shallow and infertile (W NA, the Mediterranean region)
chaparral
cactus, other low-adapted plants, less than 25 cm rainfall, soil has a coarse texture (30 degrees north and south of the equator)
deserts
coniferous and broadleaf trees, epiphytes, mosses, ferns, and shrubs, over 140 cm rainfall, soil richer than that in tropical rainforests (NA, SA, SAFR, EUR, RUS, NE ASIA, AUS, NZ)
temperate rainforest
grasses with more widely spaced trees, 10-30 cm rainfall, soil is porous and has only a thin layer of humus (AUS, SAFR, IND, half of AFR
savanna
the uppermost and most oxygenated layer in freshwater
epilimnion
lower, colder, and denser layer in freshwater
hypolimnion
demarcation line between two layers where the temperature shifts dramatically
thermocline
begins with the very shallow water at the shoreline. plants and animals that reside here receives abundant sunlight. the end of this zone is defined as the depth at which rooted plants stop growing.
littoral zone
surface of open water; the region that extends to the depth that sunlight can penetrate. organisms that are residents in this zone tend to be short lived and rely on sunlight (i.e. phytoplankton)
limnetic zone
the layer where water is too deep for sunlight to penetrate. organisms adapted to little light, colder temperatures, and less oxygen reside here.
profundal zone
the surface and sub-surface layers of the river, lake, pond, or stream bed, characterized by very low temperatures and low oxygen levels and inhabited by organisms that live on, or below the sediment surface.
benthic zone
a site where the “arm” of the sea extends inland to meet the mouth of a river
estuary
areas along the shores of fresh bodies of water; ephemeral water bodies. includes marshes, swamps, bogs, prairie potholes, and floodplains
wetlands
coastal wetlands found in tropical and sub-tropical regions; characterized by trees, shrubs, and other plants that can grow in brackish tidal waters and are often located in estuaries; has a diverse animal population
mangrove swamps
created by the buildup of deposited sediments, their boundaries are constantly shifting as water moves around them; generally the first hit by offshore storms, important buffers for the shoreline
barrier islands
formed from a community of living things; cnidarians secret a hard, calciferous shell, extremely delicate and vulnerable to physical stresses
coral reef
ocean water closest to land; between the shore and continental shelf
coastal zone
the photic, upper layers of water; warmest region if ocean water, also has the highest levels if dissolved oxygen
euphotic zone
the middle region; colder and darker and does not receive enough light to support photosynthesis
bathyal zone
the deepest region of the ocean; extremely cold temperatures and low levels of dissolved oxygen
abyssal zone
a seasonal movement of water from the cold and nutrient-rich bottom to the surface
upwellings
caused by proliferation of dinoflagellates
red tide
nutrients move through the environment in complex cycles
biogeochemical cycles
a place where a large quantity of a nutrient sits for a long period of time
reservoir
a site where a nutrient sits for only a short period of time
exchange pool
the amount of time a nutrient spends in a reservoir or an exchange pool
residency time
matter can neither be created nor destroyed
Law of Conservation of Matter
when water becomes dense enough to fall to Earth because of the pull of gravity
precipitation
water held underground in the soul or in pores or crevices in rock
groundwater
the draining away of water from
the surface of an area of land
runoff
water is returned to the atmosphere; can look like water vapor
evaporation
in plants; releases large amounts of water into the air
transpiration
animals and plants breathe in oxygen and give off carbon dioxide
respiration
plants take in carbon dioxide, water, and energy from the sun to produce carbohydrates
photosynthesis
the bodies of once-living organisms are buried deep and subjected to conditions of extreme heat and extreme pressure
oil, coal, and gas
the result of actions of certain soil bacteria; in the form of ammonia (NH3) or nitrates (NO3-)
nitrogen fixation
soil bacteria converts ammonia or ammonium into nitrites which is further converted to nitrate
nitrification
plants absorb ammonium, ammonia ions, and nitrate ions through the roots
assimilation
decomposing bacteria convert dead organisms and other waste to ammonia or ammonium ions, can be reused by plants or volatilized (released into atmosphere)
ammonification
specialized bacteria (anaerobic bacteria) convert ammonia back into nitrites and nitrates, and then into nitrogen gas and nitrous oxide gas
dentrification
local; released from rocks forms through process of chemical weathering - released in form if phosphate which is soluble and can be absorbed from the soil by plants
phosphorus cycle
any factor that controls a population’s growth
limiting factor
happening in part of the terrestrial biosphere
terrestrial cycle
a body of water receives excess nutrients; causes an overgrowth of algae and depletes the water of oxygen
eutrophication
most in rocks and salts or buries deep in the ocean in oceanic sediments, can also be found in atmosphere; volcanic eruptions, certain bacterial functions, decomposition in estuaries, and the decay of once-living organisms
sulfur cycle
organisms that can produce their own organic compounds from inorganic chemicals
autotrophs
obtain food energy by consuming other organisms or products created by other organisms
heterotrophs
organisms that are capable of converting radiant energy, or chemical energy, into carbohydrates
producers
without oxygen
anaerobic
makes food from inorganic chemicals in anaerobic environments through chemosynthesis
chemotrophs
the amount of energy that plants pass on to the community of herbivores in an ecosystem (measured in kilocalories per square meter per year)
Net Primary Productivity (NPP)
amount of sugar that the plants produce in photosynthesis - amount of energy plants need for growth, maintenance, repair, and reproduction; the rate at which producers are converting solar energy to chemical energy
Gross Primary Productivity (GPP)
organisms that must obtain food energy from secondary sources
consumers
herbivores; only consumes producers
primary consumers
organism that consumes a primary consumer
secondary consumers
organism that consumes a secondary consumer
tertiary consumers
organisms that derive energy from consuming no living organic matter such as dead animals or fallen leaves
detritivores
organisms that consumes dead plant and animal material
decomposers
decomposers that use enzymes to break down dead organisms and absorb nutrients
saprotrophs
each feeding level
trophic level
usually represented as a series of steps, producer bottom and tertiary top
food chains
only 10% of energy from each previous trophic level is transferred to the present level
10% Rule
the amount of energy available at each trophic level organized from greatest to least
energy pyramid
represents feeding relationships in ecosystems more realistically
food web
the number and variety of organisms found within a specifies geographic region, or ecosystem
biodiversity
the number of different species found in an ecosystem
species richness
the degree to which living organisms are capable of tolerating changes in their environment
Law of Tolerance
living organisms will continue to live, consuming available materials until supply of these materials is exhausted
Law of the Minimum
a field that studies species richness and diversification in isolated communities
theory of island biogeography
benefits that humans receive from the ecosystems in nature when they function properly
ecosystem services
providing humans with water, food, medicinal resources, raw materials, energy, and ornaments
provisioning services
waste decomposition and detoxification, purification of water and air, pest and disease control and regulation of prey populations through predation, and carbon sequestration
regulating services
use of nature for science and education, therapeutic and recreational uses, and spiritual and cultural uses
cultural services
primary production, nutrient recycling, soil formation, and pollination
supporting services
species whose very presence co tributes to an ecosystem’s diversity and whose extinction would consequently lead to the extinction of other life forms
keystone species
species that are used as a standard to evaluate the health of an ecosystem
indicator species
those that originate and live or occur naturally in an area or environment
indigenous species
introduced species; non-native
invasive species
ecological succession
primary succession
secondary succession
pioneer species
climax community
habitat fragmentation
edge effect
